Dr. Kenneth Davis has been selected by the Research Development Core Advisory Committee for career induction support for his project entitled, "Predicting volume status using ANP in the elderly". Dr. Davis will be finishing 2 years of Geriatric Medicine Fellowship in the Division on Aging in 1989, and outlines a program expected to extend for four years, in which he will develop clinical physiologic techniques and pilot data with which to obtain funding for independent research support. Dr. Davis proposes to work in Dr. Kenneth Minaker's laboratory examining the hypothesis that ANP blood levels will provide a clinically useful measure of the reserve capacity of the homeostatic volume-control mechanisms for maintenance of normal fluid balance. Studies will include: 1) establishing the determinants of ANP variability in the aged, 2) determining the predictability of common clinical disorders of extracellular volume control by following patients in whom ANP levels have been characterized and 3) examine the ANP responses to decreases and increases in central circulating volume. The proposed research will be conducted with Dr. Minaker, who has trained a series of Academic Geriatricians and who has extensive experience in the techniques proposed. The Subject Recruitment, Epidemiology and Biostatistics, and Radioimmunoassay cores of the GRTC will be accessed for the conduct of these studies.